Dacryocystitis is inflammation of the lacrimal sac which typically occurs secondarily to obstruction within the nasolacrimal duct and the resultant backup and stagnation of tears within the lacrimal sac.
Anatomy: Tears are produced by the lacrimal glands; paired almond shaped exocrine glands which sit in the upper lateral portion of each orbit in the lacrimal fossa, an area found within the frontal bone. The tears lubricate the eye and are then collected into the superior and inferior puncta and then drain into the inferior and superior canaliculi. From the canaliculi, the tears pass through the valve of Rosenmuller into the lacrimal sac, where they then flow down the nasolacrimal duct, through the Valve of Hasner, and finally drain into the nasal cavity.
The etiology of dacryocystitis is typically due to a nasolacrimal duct obstruction (NLDO). This can further be categorized into duration (acute versus chronic) and onset (congenital and acquired causes).
Acute and chronic refer to the duration of current symptoms, with acute usually being a time frame less than three months.
- Acute dacryocystitis usually requires systemic antibiotic therapy prior to intervention for the NLDO. In the United States, likely culprits are Staphylococcus aureus, B hemolytic Streptococcus and Pneumococcus and Haemophilus influenzae in children. In adults, the more likely causative microorganisms include Staphylococcus epidermidis, Staphylococcus aureus, Streptococcus pneumoniae and Pseudomonas aeruginosa. 
- Chronic dacryocystitis typically presents with less inflammatory signs and requires surgical therapy for the underlying cause.
Congenital and acquired refer to the onset and cause of the NLDO, which guides the treatment algorithm.
- Congenital forms of dacryocystitis are typically due to obstruction of the valve of Hasner, located in the distal portion of the nasolacrimal duct. If amniotic fluid is not expelled from the nasolacrimal system a few days following delivery, it can become purulent, leading to neonatal dacryocystitis. 
- Acquired causes of dacryocystitis include involutional changes (aging), systemic disorders (like sarcoidosis), trauma (such as nasoethmoid fractures), surgeries (such an endonasal procedures), neoplasms, and certain medications (such as timolol, pilocarpine, idoxuridine, and trifluridine).
Dacryocystitis has a bimodal distribution; most cases occur after birth (congenital dacryocystitis) or in adults greater than 40 years of age (acute dacryocystitis). Congenital nasolacrimal duct obstruction occurs in approximately 6% of newborns and dacryocystitis occurs in 1/3884 live births. In adults, females are more commonly affected than males, and Caucasians are more commonly affected than African Americans 
The risk factors for dacryocystitis are varied but are almost always related to nasolacrimal duct obstruction.
- Females are at greater risk due to their narrower duct diameter as compared to males
- Older age leads to narrowing of the punctual openings, slowing tear drainage
- Dacryoliths; often idiopathic, a collection of shed epithelial cells, lipids, and amorphous debris within the nasolacrimal system
- Nasal septum deviation, rhinitis and turbinate hypertrophy
- Damage to the nasolacrimal system due to trauma of the nasoethmoid region or endoscopic/endonasal procedures
- Neoplasm within the nasolacrimal system
- Systemic disease such as Wegener’s granulomatosis, sarcoidosis, and Systemic Lupus Erythematosus (SLE), or lacrimal sac tumors
- Medications such as timolol, pilocarpine,idoxuridine, and trifluridine
Dacryocystitis typically occurs secondary to obstruction of the nasolacrimal duct. Obstruction of the nasolacrimal duct leads to stagnation of tears in a pathologically closed lacrimal drainage system, with the stagnated tears providing a favorable environment for infectious organisms. The lacrimal sac will then become inflamed leading to the characteristic erythema and edema at the inferomedial portion of the orbit.
Symptoms and Signs
Presentation differs for acute and chronic dacryocystitis. In acute dacryocystitis, the symptoms may occur over several hours to several days and is characterized by pain, erythema, and edema over the medial canthus and the area overlying the lacrimal sac at the inferomedial portion of the orbit. The redness can extend to involve the bridge of the nose. Purulent material can sometimes be expressed from the puncta and tearing may be present. In cases of chronic dacryocystitis, excessive tearing and discharge are the most common symptom. Changes in visual acuity may be present due to tear film production
Erythema involving the entire orbit and pain with extraocular movement are not typically associated with dacryocystitis and should prompt the health care provider to search for alternative diagnoses. Extension of the mass superior to the medial canthus should also prompt imaging and further workup.
The diagnosis of dacryocystitis is generally made clinically based off of the patient’s history and physical exam, as described above. In acute cases, a Crigler, or tear duct, massage can be performed to express material for culture and gram stain. In patients who appear to be acutely toxic or those who present with visual changes, imaging and bloodwork should be considered. In chronic cases, serologic testing can be performed if systemic conditions are suspected. For example, antineutrophilic cytoplasmic antibody (ANCA) testing may be useful to test for granulomatosis with polyangiitis (formerly Wegener's), while antinuclear antibody testing (ANA) and double stranded DNA (dsDNA) can be used if systemic lupus erythematosus is suspected.  Imaging is not typically needed for diagnosis unless suspicion arises on history and physical (for example, patient complains of hemolacria). CT scans may be performed in cases of trauma. Dacryocystography or plain film dacrosystogram (DCG) can be performed when anatomic abnormalities are suspected. Nasal endoscopy is useful to rule out hypertrophy of the inferior turbinate, septal deviation and inferior meatal narrowing.
The fluorescein dye disappearance test (DDT) is another option available to evaluate for adequate lacrimal outflow, especially in patients unable to undergo lacrimal irrigation. In a DDT assay, sterile fluorescein dye if instilled into the conjunctival fornices of each eye, and the tear firms are then examined under a slit lamp. The persistence of dye coupled with asymmetric clearance of the dye from the tear meniscus after five minutes, indicates an obstruction.  However, this does not distinguish between a upper (punctal, canalicular, or sac) and lower (nasolacrimal duct) obstruction.
- Acute ethmoid sinusitis
- Infected sebaceous cysts
- Eyelid ectropion
- Punctal ectropion
- Allergic rhinitis
- Lacrimal sac or sinonasal tumor
Definitive treatment requires treating the underlying cause of the dacryocystitis. In most adults, this is a dacryocystorhinostomy (DCR) for the underlying involutional acquired NasoLacrimal Duct Obstruction (NLDO). In children, a more conservative route is typically followed as congenital NLDO has a 90% chance of resolution by 1 year of age.
First, acute dacryocystitis should be addressed, using oral antibiotics with gram positive coverage. Warm compresses and Crigler massages can also be employed in children. In both adults and children, lacrimal probing is discouraged in acute cases to prevent creation of false passages in the friable tissue. If the patient is progressing despite oral antibiotics, shows evidence of orbital cellulitis, or is otherwise complicated, this may require IV antibiotics.
Once the acute inflammation/infection is controlled, the underlying cause can be addressed. In pediatrics, this is often a blockage at the valve of Hasner, so treatment begins conservatively with Crigler massages (parents are taught how to perform the massage at home), and antibiotics are prescribed for the treatment of acute flares. 90% of cases resolve by one year with conservative measures. The patients who fail conservative treatment often undergo lacrimal probing, which is successful in 70% of cases. If still unsuccessful, additional surgical interventions may be needed, such as stenting, balloon dacryoplasty, and DCR.  DCR can be done percutaneously as an external DCR or endoscopically as an endoscopic dacryocystorhinostomy. 
Prognosis and Complications
Fortunately, the prognosis of dacryocystitis is generally positive, but devastating complications are possible, so prompt referral to an ophthalmologist is encouraged. Possible complications include the formation of lacrimal fistulas, lacrimal sac abscesses, meningitis, cavernous sinus thrombosis, vision loss, and death.
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